This invention relates to an apparatus for controlling the operation of a regenerative device to generate a quantity of heat so as to burn the exhaust particles collected in a trap located in the exhaust conduit of an internal combustion engine.
It has been proposed to purify exhaust gases from an automobile internal combustion engine by employing a trap located in the exhaust conduit of the engine to collect therein carbon or other particles of the exhaust gases. A regenerative burner is repetitively operated to burn the particles collected in the trap so as to regenerate the trap each time a regeneration requirement occurs. The regeneration requirement is determined by the pressure differential across the trap reaching a predetermined value or the pressure on the inlet side of the trap reaching a value determined based upon engine operating parameters.
One difficulty encountered with such a conventional purifying device is lack of accuracy in controlling the trap regeneration. The pressure on the inlet side of the trap and thus the pressure differential across the trap varies with variations in the rate of exhaust gas flow to the trap and the presence of an EGR system in the engine. As a result, the trap regeneration occurs sometimes with an advance causing waste of fuel in the burner and sometimes with a delay causing an abnormal rise in the exhaust gas pressure to degrade engine drivability.
Therefore, the present invention provides a trap regenerative device control apparatus which can increase the accuracy of detection of a regeneration requirement for the trap.